Andrew Mountbatten-Windsor has been served a summons compelling him to give evidence at a Turkish businessman's fraud trial, Sky News understands.
Andrew is not accused of wrongdoing.
The fraud trial is against a man who has called Andrew as a witness, as reported last month.
It is understood the former prince will be compelled to give evidence before the High Court around 15 December, either in person or by video.
It is believed that Andrew is the first royal since the 19th century to be sent such a witness summons.
Sky News has approached Andrew for comment.
The case will hear allegations made by Nebahat Isbilen, a Turkish millionaire and wife of a former politician, who says her former adviser, Selman Turk, misled her and used her wealth for his own interests.
Mrs Isbilen claims she was misled by Mr Turk over a payment of £750,000 made to the former Duke of York in 2019, which she believed was for help with a passport, according to court documents.
Mr Turk strongly denies the allegations, claiming the payment was made on Mrs Isbilen's own initiative to create goodwill with Andrew and had nothing to do with a passport.
Court documents also show that there will be questions about another payment made from Mrs Isbilen's account - about £768,743 in January 2020 - which Mr Turk says was a loan to Andrew for the purchase of a chalet in Switzerland.
Mrs Isbilen has contested that claim.
More from Sky News:
'Famous man' loses injunction bid
Slave trade 'fills my soul with sorrow', says King
Representatives for Mr Turk said: "The judge concluded that the proposed evidence that Mr Turk wishes to adduce from Mr Mountbatten-Windsor appears relevant to allegations of dishonesty advanced against Mr Turk and that, in the circumstances, it would be unfair and unjust to prevent him from seeking to adduce that evidence at trial."
They added that Mr Turk "looks forward to vindicating his position at the forthcoming trial".
Andrew's court appearance will be the first public questioning he has faced since his interview on BBC Newsnight in 2019.
The trial at the High Court is due to start later this month.
(c) Sky News 2026: Andrew Mountbatten-Windsor ordered to give evidence at businessman's fraud trial, Sky New
Parliament risks 'catastrophic event' without urgent renovation, MPs warn
Students to be offered Ukrainian GCSE to preserve cultural heritage
Bomb threats reported on multiple flights, including two from UK airports
Spain's transport minister Oscar Puente to resign after train crash killed 69 people
Tenerife footballer Jesus de Miguel, 30, dies after on-field collision
Reform councillor charged with 35 offences including 12 counts of rape
Third teen arrested on suspicion of attempted murder after five boys stabbed at Halloween party
Cyber attacks affect UK meat processing industry, top security official says
